Toy building unit



FIG. 1 is a top plan view of a first embodiment of a toy building unitshowing the new design, a bottom plan view, a right-side elevationalview, a left-side elevational view, a front elevational view, and a rearelevational view thereof being mirror images thereof; and,

FIG. 2 is a perspective view thereof.

The ornamental design for a toy building unit, as shown and described.